Filter tips for cigarettes



May 23, 1957 D. w. MoLlNs 3,320,960

FILTER TIPS FOR CIGARETTES Filed Jan. 19, 1965 United States Patent O 5,370/64 8 Claims. (Cl. 131-265) This invention relates to filter tips for cigarettes.

Hitherto, filter tips for cigarettes have most frequently contained simple mechanical ltering media, e.g. paper or cotton wool, but recently increased demand for more efiicient filtration has led to consideration of other media and in particular eomminuted (i.e. powdered or granulated) materials, notably granulated carbon.

A filter tip containing carbon granules needs to have two short conventional filter plugs within an enclosing paper wrapper, the plugs and wrapper enclosing a space serving to receive the carbon granules. Such tips may be manufactured on a machine of the continuous rod type which places plugs at suitably spaced intervals on a moving web of wrapping paper, carried by a conveyor belt, and thereafter feeding the web with the plugs through a so-called garniture in which stationary deiiector blades cause the paper first to assume a U formation and then be folded into a cylinder enclosing the plugs; the paper is of course overlapped and supplied with adhesive along one longitudinal edge portion as the cylindrical form is approached so as to provide a properly sealed seam to close the cylinder.

Carbon granules (or other granulated or powdered filter material) are fed into each of the spaces between successive plugs when the paper adjoining such space has been brought to the U formation but before any overlap of the paper edges has been produced. For various practical reasons, it has been found difficult to achieve complete filling of said spaces, hence when such a filter tip, assembled into a cigarette, is in use, itis possible for smoke to pass unfiltered between the plugs as there is an empty space above the carbon or other granules.

It is an object of the present invention to provide an improved form of filter tip containing granulated or powdered filter material between two conventional filter plugs, wherein means are provided for ensuring that no substantial proportion of smoke passing between said plugs can avoid filtration by said material.

According to the invention we provide a composite filter tip for cigarettes, comprising two filter plugs held in axially aligned but spaced relation to one another by a paper or like wrapper forming a tube enclosing both said plugs and comminuted (i.e. granulated or powdered) filter material retained within said wrapper in the space between said plugs, including a facing of resilient or deformable material attached to and covering at least part of the inner face of the wrapper, the thickness of said facing being such in relation to the quantity of filter material that the facing is at least slightly compressed so that said facing is pressed against said part of the inner face of the wrapper to oppose passage of smoke therebetween.

The material employed for said facing may for example be crepe paper, or a foamed synthetic plastic material. It will be appreciated that, so long as some compression of the facing is obtained as specified above, the granulated or powdered material must fill the space within the part of the wrapper carrying the facing, hence smoke must pass through said material in travelling from one plug ice N to the other. The facing material must of course be impermeable, but this requirement is not absolute, e.g. crepe paper will allow passage of smoke to a certain extent; the material for the facing must in practice be selected on the basis that it should have a substantially greater resistance to passage of smoke than is offered by the granulated or powdered filter material to be used.

In order that the invention may be well understood, preferred embodiments thereof will now be described, with reference to the accompanying drawings, in which:

FIGURE 1 shows in section a filter tip with a facing on the inner face of its wrapper;

FIGURE 2 shows a modification of the tip of FIG- URE l; and

FIGURE 3 shows a modification of the tip of FIG- URE 1.

First considering FIGURE l, a tubular paper wrapper l encloses two filter plugs 2, holding said plugs in axially aligned but spaced relation. The inner face of the wrapper 1, over that part of its length which surrounds the space between the plugs 2, has adhesively secured to it a facing 3 of crepe paper. Said space is filled with granulated carbon 4, in such quantity that the crepe paper facing 3 is slightly compressed and hence pressed against the inner face of the wrapper 1 to provide a seal opposing passage of smoke.

It will be seen that smoke may not pass between the plugs 2 without passing through the granulated carbon 4, except by passing between the fibres of the facing 3 which offer so much greater resistance to :such passage than does the granulated carbon that in practice no significant proportion of the smoke will pass through the facing.

FIGURE 2 shows a filter tip generally similar to that of FIGURE l but here the facing 3 does not cover the whole of the inner face of wrapper 1 surrounding the space in which the granulated carbon 4 is accommodated; instead two rings of facing 3a, 3b, are provided, adjacent to the plugs 2, leaving uncovered a central annular zone 5 of the inner face of the wrapper.

The foregoing detailed description is given purely by way of example, various changes and modifications being possible without departure from the scope of the invention. Thus for example in the form shown in FIGURE 1, the facing need not extend over the whole of the part of the inner face of the wrapper surrounding the space containing the granulated carbon, but an annular strip of said inner face may be left uncovered adjacent to each plug, as illustrated in FIGURE 3.

What I claim as my invention and desire to secure by Letters Patent is:

1. A composite filter tip for cigarettes, comprising two `filter plugs, a wrapper forming a tube enclosing both plugs to hold the latter in axially aligned but spaced relation to one another, comminuted filter material retained within said wrapper in the space between said plugs, and a facing of deformable material attached to and covering at least part of the inner face of the wrapper, the thickness of said facing being such in relation to the quantity of filter material that the facing is at least slightly compressed so that said facing is pressed against said part of the inner face of the wrapper to oppose passage of smoke therebetween.

2. A tip as claimed in claim 1 in which the facing is of crepe paper and covers the whole inner face of that part of the wrapper which surrounds the space between the plugs.

3. A tip as claimed in claim 1, in which the material employed for said facing is crepe paper.

.w "2 l 4. A tip as claimed in claim 1, in which the material References Cited by the Examiner employed for said facing is a foamed synthetic plastic UNITED STATES PATENTS material.

5. A tip as claimed in claim 1, in which the facing 2064239 12/1936 Alvaz 131n264 covers the whole inner face of that part of the Wrapper 5 2815760 12/ 1957 Schreus et al Bln-262 3,079,926 3/1963 Litcheld et al 131--10.7 Whlch surrounds the space between the plugs.

6. A tip as claimed in claim 1, in which the facing com- FOREIGN PATENTS prises two rings adjacent to the plugs. 377,147 7/ 1932 Great Britain. 7. A tip as claimed in claim 1, in which the facing is 741,416 12/ 1955 Great Britain.

arranged to leave uncovered an annular strip of the inner 10 531,511 8/1955 Italy.

face of the Wrapper adjacent to each of the plugs.

8. A tip as claimed in claim 1, in which the lter ma- SAMUEL KOKEN Primary Exammerterial is granulated carbon. D. J. DONOHUE, Assistant Examiner. 

1. A COMPOSITE FILTER TIP FOR CIGARETTES, COMPRISING TWO FILTER PLUGS, A WRAPPER FORMING A TUBE ENCLOSING BOTH PLUGS TO HOLD THE LATTER IN AXIALLY ALIGNED BUT SPACED RELATION TO ONE ANOTHER, COMMINUTED FILTER MATERIAL RETAINED WITHIN SAID WRAPPER IN THE SPACE BETWEEN SAID PLUGS, AND A FACING OF DEFORMABLE MATERIAL ATTACHED TO AND COVERING AT LEAST PART OF THE INNER FACE OF THE WRAPPER, THE THICKNESS OF SAID FACING BEING SUCH IN RELATION TO THE QUANTITY OF FILTER MATERIAL THAT THE FACING IS AT LEAST SLIGHTLY COMPRESSED SO THAT SAID FACING IS PRESSED AGAINST SAID PART OF THE INNER FACE OF THE WRAPPER TO OPPOSE PASSAGE OF SMOKE THEREBETWEEN. 